1. Field of the Invention
The present invention relates to a service retrieval apparatus which provides information indicating which server provides what kind of service in a network to a client which is intended to receive the service, and a method therefor.
2. Description of the Related Art
A wide area computer network represented by the Internet is not a uniform single network. It is constituted as an aggregate in which a large number of networks with different operators are mutually connected and logically hierarchized. Types of networks constituting the wide area computer network include an IP (internet Protocol) sub-network, a domain, a company intranet, an ISP (Internet Service Provider), and the like. Each network is operated according to network system designs and operation policies that are different from each other. The mutual connection of the networks is performed by a network relay apparatus such as a router or a firewall and, at the same time, mutual interference of the networks is prevented by the network relay apparatus.
A service provided for supporting an application via a network (hereinafter referred to simply as “service”) is generally provided by a server connected to the network. Thus, the service has both an aspect of a service in a network space and a server in a geographical space. Usually, a network where a certain service is located and a geographical place where a server providing the service is located are not in a direct dependency relation. A mutual connection relation among networks depends upon organizations operating the networks. Therefore, even if servers providing certain services are located in places geographically close to a client, networks to which the servers are connected, respectively, may be different.
Since a service is identified according to a location on a network (network address, domain name, URL (Uniform Resource Locator), etc., hereinafter referred to as “service location”), a user or a client apparatus (e.g., scanner, device control apparatus) uses respective services by designating a service location.
Even if services are of the same kind (e.g., print service), service attributes such as quality (e.g., resolution), performance (e.g., paper discharge speed), an additional function (e.g., presence or absence of a sorter), a communication protocol (e.g., various print protocols), a license (e.g., presence or absence of an access right), and cost are different depending on the service or the server. Therefore, in using a desired service, a user goes through stages of clarifying contents which the user should request such as desired specific service attributes, that is, restricting conditions (e.g., protocol to be supported, type of billing to be used), or measurement criteria to be minimized or maximized (e.g., cost, quality), comparing the contents to be requested and service attributes of each service, selecting one service which satisfies the request and then, specifying a service location where the user can be provided with the service.
Unlike a service provided by each server, a retrieval service provided by a service retrieval apparatus is a service for supporting these stages in the case in which a user does not have knowledge concerning a service location or service attributes such as the case in which a user makes connection to a network for the first time or the case in which a user makes connection to a network temporarily in a place the user has moved to or the like. In other words, by providing the retrieval service, the service retrieval apparatus informs the user of one or more servers capable of providing a service desired by the user. However, when the service retrieval apparatus specifies a server, geographical information of the server, that is, a geographical location where the server is located may be a restricting condition for the user or a client apparatus wishing to use the service. A representative example of such a service is a print service. In the print service, it is necessary to consider a locational problem in that where paper is discharged in selecting a server providing the print service in order to output a processing result to a physical medium such as paper.
Japanese Patent Application No. 2001-284485 (hereinafter referred to “commonly assigned application”), which was filed by the same applicant, describes a method of providing information on what kind of services are provided by respective servers connected to a network to a user who intends to be provided with a service. In the service retrieval method described in this application, a range to be a target of retrieval in the network is set, disclosed service information is retrieved in the set retrieval range, and information such as service locations and service attributes obtained as a result of the retrieval is provided to a user.
Incidentally, depending upon retrieval conditions designated by a user, it is possible that a service satisfying the retrieval conditions does not exist in a retrieval range set in the conditions. In this case, a notice to the effect that no service conforming to the retrieval conditions exists is returned to the user. The user having received such a retrieval result resets a retrieval range or changes the retrieval conditions to request a retrieval service again in order to find a desired service.
On the contrary, depending upon retrieval conditions designated by a user, it is possible that services satisfying the retrieval conditions exist in an extremely large number in a retrieval range set in the conditions. In this case, information on the extremely large number of service is returned to the user. The user having received such a retrieval result resets a retrieval range or changes the retrieval conditions to request a retrieval service again in order to narrow down the information. Note that a technique related to this application is described in Japanese Patent Laid-Open Publication No. 2000-312222.
As described above, the user is inconvenienced because, when contents of the processing result of the retrieval service obtained by requesting the retrieval service are not satisfactory, the user has to reconsider and reset retrieval conditions, and then send a retrieval request again.
In addition, the processing result of the retrieval service is outputted to a screen or a print medium to be confirmed by the user. However, it is inconvenient if the processing result of the retrieval service is outputted in a state in which it can not easily used, even if the contents of the processing result of the retrieval service are satisfactory.